1. Field of the Invention
The present invention relates to a mail processing apparatus, and more particularly, to an apparatus for itentifying postage stamps based on identifying the color information contained in the stamps.
2. Prior Art
An automatic mail processing apparatus has been developed in which a postage stamp affixed on a mail article is detected and the type of the detected stamp is identified so as to determine the type of the mail article (ordinary mail or express mail) and whether or not the appropriate postage is affixed. According to the prior art, postage stamps are generally detected according to one method based on the luminescence of luminescent stamps, such as fluorescent or phosphorescent stamps. Another method relies on a special mark printed on each stamp, and yet a further method relies on detecting the predetermined color of each type of stamp. However, the first method has a disadvantage in that the cost of producing the stamps is increased, and the other methods suffer from a problem in that the design of the postage stamps is limited.
In Japan, each regular postage stamp has a frame of a specific color associated with its postage, and this specific color frame is detected to determine the type of the postage stamp. This method also restricts the design of the stamps. All stamps including commemorative stamps must have a specific color frame. Stamps having no specific color frame cannot be detected in the prior art processing apparatus.